One way to go for this would be using Android Device Manager, but in my experience with it so far, I have noticed that it requires an active internet connection. Otherwise it wouldn't show the location.

The other way would be using the IMEI number of your device to track it - if you have it with you, that is. You can contact your local law enforcement agency and request them to track it in that case.

FYI - you can get your IMEI by dialing "*#06#" from the dialer screen.

Google just released this: Android Device Manager. It is a native app and should either be on your device now or coming soon. Find your phone and/or wipe it. Just go to google.com and google: "Android Device Manager". You'll get a google site with full tutorial. Slick!